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This paper presents the numerical simulation of a model with one bolt connecting two or three plates using the finite element method. This unitary model with one bolt is validated by comparing its results with those obtained in the literature for three different types of applied load: tension, shear, and a combination of both. The results are also compared with the American and Brazilian design codes. The unitary model includes all necessary considerations: contacts between the plates and the nut, head and shank of the bolt; contact between the plates, as well as the friction between them; and pre-load on the bolt. Moreover, it responds properly to forces parallel and perpendicular to the contact surface between the plates including prying action effects and slip. These calibrated models can be then introduced on a model that represents a full connection through a relatively simple process using ANSYS APDL language, thus allowing the study of any bolted connection type.

Fatigue assessment of existing bridges is increasingly prominent due to the advanced age and larger traffic demands. The Hercilio Luz Bridge (HLB), which was built in 1926, was closed to traffic in 1991 due to high corrosion levels and deterioration of critical structural elements. A complete rehabilitation project was developed for the bridge which included the replacement of the compromised members and strengthening of the foundations. In this paper, a fatigue life evaluation was carried out using fatigue load models 3 of the Eurocode EN 1991-2 to obtain the calculated stress ranges for the critical members of the bridge, as well as the simplified equivalent stress range and fatigue damage accumulation method for the fatigue safety verification defined by Eurocode EN 1993-2 and Eurocode EN 1993-1-9. Fatigue provisions, such as such truck geometry, S-N curves, fatigue category, etc., are reviewed. The evaluation results reveals that the stringer-to-floor-beam connections near the transition point of the eyebar chain are susceptible to fatigue damage. Besides, the number of cycles caused by a single truck prescribed in Eurocode is conservative.

A performance trial (88 days) was undertaken to evaluate the effects of replacing fishmeal (FM) and/or fish oil (FO) in a practical formulation for juvenile meagre with a mixture of plant proteins (PP) and vegetable oils (VO), in terms of growth performance, nutrient utilization, intestinal structure and functionality and several haematological stress indicators. Twelve homogenous groups of 75 meagre (mean initial body weight: 55.4 ± 3.5 g) were fed one of four isonitrogenous (51% DM), isolipidic (17% DM) and isoenergetic diets (22.9 MJ · kg − 1 DM). A FMFO diet was formulated with high levels of marine protein sources (45%) and fish oil as the sole fat source. Based on this formulation, 60% of fish oil was replaced by a blend of vegetable oils (diet FMVO). Two other diets were formulated with a 50% replacement of marine proteins by plant protein sources. One of these plant protein-rich diets contained fish oil as the sole fat source (PPFO), while in the other 60% of fish oil was replaced by a blend of vegetable oils (PPVO). Growth of meagre was not significantly affected (P > 0.05) by the replacement of fishmeal and fish oil by ingredients of vegetable origin. Meagre fed the plant-protein rich diets (PPFO and PPVO) showed a significant enhancement (P 0.05) on FE, PER and nutrient retention. Dietary treatments had no effect (P > 0.05) on the whole-body composition of fish. This good tolerance towards plant protein sources exhibited by meagre was further corroborated by the apparent digestibility data of individual ingredients. As expected, fish fed the blend of vegetable oils showed a reduction of total n-3 series fatty acids and a concomitant increase of total n-6 series fatty acids. Dietary changes on both protein and lipid sources did not affect (P > 0.05) intestinal morphology, activity of intestinal brush border enzymes and selected haematological stress indicators in fish. Signs of liver steatosis were found in meagre, but not directly associated to dietary changes of protein and lipid sources. Meagre showed a good ability to cope with vegetable based diets. However, although not statistically significant in this short-term trial, present data also suggests possible detrimental effects on fish performance associated to concomitant high inclusion levels of plant protein and vegetable oils.

Sustainability is a fundamental topic to be addressed in the establishment of a market for jet biofuels in Brazil. The objective of this paper is to enhance the discussion on sustainability of biofuels, and to discuss the main gaps to meet the requirements of sustainability for four groups of feedstock: sugars and starch, oil, lignocelluloses, and wastes. Some general common conclusions can be made for all the analyzed feedstock. In the social sphere, the main positive impacts are the high potential for job creation, income generation and regional development. Regarding the gaps for compliance with sustainability requirements, the following aspects were common to all groups of feedstock: great number of laws and rules; different interpretations and lack of knowledge on how to apply some laws; certain labor laws not adapted to the rural context. The main potential positive impact generated by compliance with requirements is greenhouse gas (GHG) emissions reductions compared to fossil fuels.